In known closed busbar systems of this type, the arrangements prepared with respect to the length of the phase bars and with respect to the number of branch bars are capped with for example an epoxy resin and housed in a switch cabinet. Thereby, any subsequent corrections and/or extensions are not possible. In addition, the number of the branch bars to be provided must already be known in the design phase. Furthermore, in such capped busbar systems, the problem associated with heat development for example due to short-term increase in power is not solved in particular in southern countries.